Developmental Milestones

Visual
pathways containing connections between the eye and the brain are
in place but function with limited capacity.

Refinements
occur in these pathways both in terms of speed of conduction (due
to increased nerve myelination) and improved processing of
information through increased neural connections.

As
visual pathways develop they become more efficient and responsive
leading to improved vision
.

Visual
functions develop rapidly as the infant receives and processes
visual information usually within less than one month of age.

The
basic focusing structures are present within the eye. However,
the nerve cells of the sensitive retinal areas needed for fine
vision are not fully developed compared to peripheral retinal
areas that have a much coarser capacity for resolution.

Sensory Development

Infants
are able to see outlines of objects but the ability to resolve
details in objects (visual acuity) and the ability to detect
contrast are only a fraction of what they are in adults. These
functions however show rapid improvement shortly after birth.

By
2 months infants can distinguish their mother’s face from
that of a stranger’s.

By
3 months, internal details of objects become more apparent,
infants start to focus on facial details such as eyes.

Red/green
colour discriminations emerge first.

By
6 months infants start to see with both eyes together allowing
for the emergence of depth perception.

Colour
vision is weak or absent, vision is close to black and white at
birth. However the ability to discriminate a wide range of
colours is present by 3 months.

Oculomotor Development

Accommodation
(the ability to focus over a range of distances) is limited and
almost fixed at birth.

Accommodation
increases to adult-like ranges by 3 months, and accuracy by 6
months. (The improvement pertains primarily to the improvement in
their spatial vision).

By
3 months of age infants can follow a moving object smoothly,
similar to adults.

Visual Development

Between
birth and 2 months infants clearly demonstrate an alert state,
taking in information around them.

Improvements
in spatial orientation and attending to objects are seen between
2 and 6 months from birth.

Specific
modifications (some expansion, some refinement) to visual brain
regions and the pathways that connect them to the eye correlate
with a steady improvement in visual functions.

The
eye itself continues to grow and the size, shape and distribution
of cells in the retina lead to improvements in visual acuity.

As
the eye grows errors of focus steadily decrease.

Sensory Development

As
brain structures and pathways continue to develop so too vision
continues to improve.

The
development of these brain structures allows for spatial
discrimination (visual acuity, contrast, colour), motion
perception, and depth perception.

Visual
performance is also increased due to maturation and refinement
along the visual pathway where better connections are made
through increased visual activity.

Visual
acuity can be measured more accurately as a child’s
cognitive and behavioural levels increase. A visual crowding
effect is found where seeing a letter is harder when its
surrounded by other letters or objects.

Development of Focus

‘Normal’
vision in children is different from normal vision in adults.

Astigmatism
(uneven focus) declines
.

Farsightedness
is still the norm in most children. Focus is often best and
individual differences the least when children reach 5 to 6 years
of age.

Visual Attention

Infants
become able to shift attention from near to far distances and
from one object to another, and from a whole object to fine
details.

By
12 months of age, infants can pay attention to objects that are
pointed out to them.

Attention
in toddlers becomes wilful and effortful.

Preschoolers
become proficient at selectively focusing on relevant information
while ignoring irrelevant or conflicting information.